Discharge regimes and density jumps in a helicon plasma source

Abstract

Summary form only given. A high density plasma source using a helicon wave is becoming very attractive in plasma processing and confinement devices. In the previous work (Shinohara, 1997, Shinohara et al., 1995, 1996 (2), 1997), the characteristics of this wave and plasma performance with diameters of 5 and 45 cm have been studied, and the helicon wave was only observed after the density jump. Recently, density jumps from the low to high electron densities with a level of 10/sup 13/ cm/sup -3/ were investigated by changing the antenna wavenumber spectrum (Shinohara et al., 1998), and the obtained results were compared with the inductively coupled plasma (ICP). However, the mechanisms of density jumps and plasma production are still open questions to be answered. Here, we try to investigate the discharge regimes and density jumps in a helicon plasma source, by changing the antenna wavenumber spectrum (two-loop antenna with the same or opposite current directions), At filling pressure (P=6 and 51 mTorr) and the external magnetic field (B/spl les/1 kG). The plasma was produced in a Pyrex tube with a diameter of 5 cm by RF with a frequency of 7 MHz.